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The Feedzone with Monique Ryan: Feed your head
Cyclists rightfully focus their dietary attention on consuming the properfoods in adequate amounts so that they can sustain energy during long trainingrides, and replenish muscle fuel stores and recover nutritionally duringthe season. But you should also consider how your daily food intakeand on-bike nutrition can affect and feed your brain. Just like your heart,your brain is an organ that benefits from optimal nutritional care. Nutritioncan affect brain chemicals, brain cell structure and function and theability of the brain to transmit electrical messages. Though nutritionalneuroscience is relatively young, specific foods can feed your head, preventbrain drain, and even provide a central nervous system boost during training.
Your Brain
Despite being one of the most complex organisms in the body, your brainis the organ that we know the least about. Your brain consists of abouta hundred billion neurons surrounded by glial cells whose main role isto provide the neurons with energy. Neurons communicate with each otherby electrochemical signals. The connections between our neurons are rapidlyand constantly changing and re-wiring and we does lose brain cellseveryday as we age. What else is in your brain? The membranes of neuronsare composed of a double layer consisting mainly of fatty acid molecules.Myelin is the protective sheath that surrounds neurons, and about 70-percentof it is composed of fat. Fat provides a good form of insulation and allowsyour neurons to operate at high speed.Fuel
Another important question is “What does your brain run on?” The answeris almost entirely on glucose (except in cases of starvation). Your brainis very active metabolically and normal blood glucose levels ensure anadequate supply of fuel to the brain. When blood glucose levels run relativelylow, a shortage can occur. Have you ever postponed eating, or missed breakfastand then felt your whole brain come alive when you finally sat down fora meal or snack? Perhaps a headache eases up and your concentration andfocus return. Under normal conditions at rest, your brain and nervoussystem require a minimum of 150 grams of glucose daily.Your brain power benefits when you consume meals and snacks on timeor at regular intervals. A carbohydrate boost raises blood glucose levelsand also stocks some back-up fuel in the liver as glycogen. One of thebiggest brain drain mistakes you can make is skipping breakfast, or notconsuming enough for breakfast. When you wake up in the morning liver glycogenstores are low and breakfast not only boosts blood glucose levels, butalso restocks our liver glycogen supply. From your morning meal onward,eating every three to five hours seems to offset the waxing and waningof blood glucose levels. Of course, you need to plan meal and snack timingaround your own training and work schedule. It is also important that youconsume moderate portions of nutrient dense whole grains, fruits and vegetables.A large portion of your brain is also fluid, so your daily hydration effortsare also a good brain strategy.Iron
While the brain is big on glucose utilization, many other nutrientscontribute to the brain’s correct functioning. Your brain is also a biguser of oxygen. Adequate oxygen means that your brain cells can metabolizefuel for energy and iron deficiency or anemia is linked to a shortenedattention span and mental sluggishness. Iron is also needed for the manufactureof brain proteins. Several blood tests can verify iron status. Mayfemale athletes require more iron than they consume in their diet, andare much more likely to be iron deficient than iron overloaded. In contrast, male athletes may consume more iron than they actually need, and theirrisk for iron overload is greater than that for developing anemia. Ironoverload, or hemochromatosis results in excess iron absorption and cancause organ damage, and 1-in-200 white males carry the gene for this condition.If your physician does determine that you are iron deficient and need moreiron in your diet, iron rich foods include lean red meat, pork, poultry,legumes, raisins, dried apricots, and iron fortified cereals. Iron supplementationshould be done under a physician’s guidance.B Vitamins
Many B vitamins are linked to optimal brain and nerve function. VitaminB12 is essential for a healthy nervous system, and a deficiency of thisnutrient can result in brain tissue degeneration, as well as that of thespinal cord and peripheral nerves. Animal foods such as milk, cheese, yogurt,beef, and poultry supply plenty of B12. Vegans may need to ensure an adequateintake of foods fortified with B12 or take a B12 supplement.Another important vitamin is B6 or pyridoxine which is required fornormal nervous system development from conception to adulthood. Good foodsources of B6 include wheat germ, whole grain cereals, pork, legumes, potatoes,bananas, and oatmeal. Niacin plays a role in the manufacture of many nervechemicals, and good sources are chicken, salmon, peanut butter, and wheatgerm. Pantothenic acid forms a coenzyme involved in the transmission ofnerve impulses and is found in meat, poultry, fish, whole grain cereals,legumes, milk, vegetables, and fruit. Another B vitamin thiamine, is alsoessential for healthy brain cells and is found in whole grains and enrichedbread, rice, pasta, cereal, and in pork. Finally, the B vitamin folic acidis important, as it helps to maintain blood choline levels. Choline ispart of acetylcholine, an important neurotransmitter in the brain. Folicacid is found in orange juice,, dried beans such as kidney beans, and darkleafy green vegetables like spinach, asparagus, and broccoli. Food sourcesof choline include peanuts, eggs, cauliflower, soybeans, and oatmeal.Antioxidants
Free radicals, which are highly reactive substances that need to bekept in check, are generated in our brain. Antioxdiant nutrients can deactivatefree radicals and reduce the stress they place on our bodies. It has beentheorized that free radical formation plays a role in the deteriorationof the brain. Vitamin C and beta-carotene are two potent free radicalsand are found widely in fruits and vegetables. Aim for over six servingsdaily. Some potent sources of a variety of antioxidants such as flavonoidsinclude blueberries, blackberries, cranberries, raspberries, broccoli,oranges, red grapes, red bell peppers, and kiwis. Vitamin E another potentantioxidant can be found in liquid vegetable oils, wheat germ, avocado,almonds, and sunflower seeds.Good Fats
Once again, including an ample supply of omega-3 fatty acids in yourdiet, with fish oil being the best source, offers another health benefits.While the mechanisms are not clear, Omega-3’s appear to enhance brain cellcommunication.Brain drain during training
As a cyclist, you should also consider that brain fatigue can occurduring long training rides and races. At the very least, maintaining concentrationand focus is important during harder efforts on the bike. Fortunately,all the skills that you have developed for fueling on the bike can helpoffset brain fatigue. That carbohydrate laden sports drink not only providesfuel for your muscles when glycogen stores run low, but is good brain fodderas well.When you consume carbohydrate during training, you can help lessen anincrease in free fatty acids in your bloodstream, as carbohydrate becomesthe preferred fuel source. When the concentration of fat in the blood decreases,the concentration of free tryptophan also declines. Trytophan is an aminoacid that the brain converts to serotonin. When more serotonin is producedit is believed there is an increase in “central” or brain fatigue.So by consuming the carbohydrate, you squash the steps that lead to anincrease of serotonin in the brain.Carbohydrate intake during exercise also lowers blood levels of thehormones glucagon and cortisol, and increase insulin. These changes inhormone levels would be expected to decrease levels of ammonia in the bloodand brain. Ammonia is toxic to the brain and likely also impairs musclemetabolism.Maintaining a good supply of glucose to the brain during exercise canalso result in lower ratings of perceived exertion- a given intensity ofexercise does not seem as hard. Adequate carbohydrate intake during exercisecan also go a long way to improve motivation and mood.During exercise there is also an increase in adenosine, a normal cellcomponent regulated mainly by ATP metabolism, and which contributes tocentral fatigue by inhibiting the release of neurotransmitters that stimulatethe brain, especially dopamine. Caffeine is a strong antagonist to adenosineand it is believed that one of the most important ways in which caffeineenhances performance during exercise is through stimulation of the centralnervous system by blocking adenosine receptors in the brain.While more research is needed on nutrition and the brain, a balanceddiet that provides a variety of B vitamins, plenty of antioxidant richsources of fruits and vegetables, and adding more fish to your diet areall good brain food strategies. During training staying on top of carbohydratereplacement by consuming a sports drink not only offsets glycogen depletion,but delays brain fatigue. Aim for 4 to 8 ounces of a sports drink every15 to 20 minutes. In addition caffeine intake prior to exercise, at a moderatedose of 3 to 5 mg/kg of body can also offset brain fatigue. Research oncaffeine consumption during exercise indicates that 1.5 mg/kg of body weightimproves performance.
Monique Ryan, MS, RD, LDN is a nationally recognized nutritionistwith over twenty-two years of experience and is owner of Personal NutritionDesigns,
a Chicago based nutrition consulting company that provides nutritionprograms for endurance athletes across North America (www.moniqueryan.com).Monique consults with the Chicago Fire Soccer Team, and was the nutritionistfor Saturn Cycling from 1994 to 2000. She has also consulted with the Volvo-CannondaleMountain Bike Team, the Gary Fisher Mountain Bike Team, and the RollerbladeRacing Team. Monique has consulted with USA Cycling, and was a member ofthe Performance Enhancement Team for the Women’s Road Team leading to the2004 Athens Olympics. She has also provided nutrition consultation servicesto USA Triathlon for coaching clinics, athlete clinics, and for the residentathlete team and was a member of the USAT Performance Enhancement Teamfor the 2004 Athens Olympics. Monique is the author of "SportsNutrition for Endurance Athletes," 2nd edition (March 2007), from VeloPress,which provides sports specific nutrition for road cycling, mountain biking,running, triathlon, swimming, rowing, and adventure racing. She is alsoauthor of "PerformanceNutrition for Winter Sports" (PeakSports Press), "Performance Nutritionfor Team Sports" (PeakSports Press), and "Complete Guide to Sports Nutrition."Monique is a regular contributor to VeloNews, Inside Triathlon,Outside, and ACE Fitness Matters. As part of the FeedZonecolumn, Monique will answer selected questions online. Please sendyour questions to RyanWebQA@aol.com.
